Read scraper modules from user data directory

This allows users to add scrapers without setting up a complete Python
development environment.

dosagelib/cmd.py

@@ -3,7 +3,11 @@
 # Copyright (C) 2012-2014 Bastian Kleineidam
 # Copyright (C) 2015-2020 Tobias Gruetzmacher
 import argparse
+import contextlib
 import os
+from pathlib import Path
+
+import appdirs
 
 from . import events, configuration, singleton, director
 from . import AppName, __version__
@@ -36,6 +40,10 @@ strips of all of them:
 """
 
 
+# Making our config roaming seems sensible
+userdirs = appdirs.AppDirs(appname=AppName, appauthor=False, roaming=True)
+
+
 def setup_options():
     """Construct option parser.
     @return: new option parser
@@ -230,6 +238,7 @@ def run(options):
     if not options.comic:
         out.warn(u'No comics specified, bailing out!')
         return 1
+    add_user_scrapers()
     if options.modulehelp:
         return display_help(options)
     if options.vote:
@@ -237,8 +246,37 @@ def run(options):
     return director.getComics(options)
 
 
+def add_user_scrapers():
+    """Add extra comic modules from the user data directory. This uses two
+    different locations: The "system-native" location and paths matching the
+    XDG basedir spec. While XDG isn't a thing on macOS and Windows, some users
+    (and developers) like to use these paths cross-plattform, therefore we
+    support both."""
+    dirs = set()
+    dirs.add(userdirs.user_data_dir)
+    with xdg_system():
+        dirs.add(userdirs.user_data_dir)
+    dirs = (Path(x) / 'plugins' for x in dirs)
+    for d in dirs:
+        allscrapers.adddir(d)
+
+
+@contextlib.contextmanager
+def xdg_system():
+    """context manager to do something with appdirs while forcing the system to
+    be "linux2", which implements the XDG base dir spec.
+    """
+    oldsys = appdirs.system
+    appdirs.system = 'linux2'
+    try:
+        yield
+    finally:
+        appdirs.system = oldsys
+
+
 def do_list(column_list=True, verbose=False, listall=False):
     """List available comics."""
+    add_user_scrapers()
     with out.pager():
         out.info(u'Available comic scrapers:')
         out.info(u'Comics tagged with [{}] require age confirmation'

requirements.txt

@@ -1,3 +1,4 @@
+appdirs
 colorama
 imagesize
 lxml>=4.0.0

setup.cfg

@@ -32,6 +32,7 @@ project_urls =
 [options]
 packages = find:
 install_requires =
+    appdirs
     colorama
     imagesize
     lxml>=4.0.0

tests/conftest.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: MIT
 # Copyright (C) 2019-2020 Tobias Gruetzmacher
 import time
+from pathlib import Path
 
 import pytest
 
@@ -12,3 +13,14 @@ def _nosleep(monkeypatch):
         pass
 
     monkeypatch.setattr(time, 'sleep', sleep)
+
+
+class FakeAppdirs:
+    @property
+    def user_data_dir(self):
+        return str(Path(__file__).parent / 'mocks')
+
+
+@pytest.fixture()
+def _noappdirs(monkeypatch):
+    monkeypatch.setattr('dosagelib.cmd.userdirs', FakeAppdirs())

tests/test_dosage.py

@@ -26,16 +26,22 @@ def cmd_err(*options):
     assert cmd(*options) == 1
 
 
-@pytest.mark.usefixtures("_nosleep")
+@pytest.mark.usefixtures('_nosleep', '_noappdirs')
 class TestDosage(object):
     """Test the dosage commandline client."""
 
     # This shouldn't hit the network at all, so add responses without mocks to
     # make sure it doesn't do that
     @responses.activate
-    def test_list_comics(self):
-        for option in ("-l", "--list", "--singlelist"):
+    @pytest.mark.parametrize(('option'), [
+        ('-l'),
+        ('--list'),
+        ('--singlelist'),
+    ])
+    def test_list_comics(self, option, capfd):
         cmd_ok(option)
+        out, err = capfd.readouterr()
+        assert 'ADummyTestScraper' in out
 
     @responses.activate
     def test_display_version(self):

tests/test_modules.py

@@ -11,12 +11,13 @@ from dosagelib.plugins.s import SoloLeveling
 from dosagelib.plugins.smackjeeves import SmackJeeves
 from dosagelib.scraper import GeoblockedException
 
+
 def cmd(*options):
     """'Fake' run dosage with given options."""
     assert dosagelib.cmd.main(("--allow-multiple",) + options) == 0
 
 
-@pytest.mark.usefixtures("_nosleep")
+@pytest.mark.usefixtures('_nosleep', '_noappdirs')
 class TestModules(object):
     """Test that specific comic modules work correctly."""